ttl number in ping result.

bruse · 11-17-2005, 06:25 AM

[root@localhost root]# ping 10.255.240.131
PING 10.255.240.131 (10.255.240.131) 56(84) bytes of data.
64 bytes from 10.255.240.131: icmp_seq=1 ttl=128 time=0.559 ms
64 bytes from 10.255.240.131: icmp_seq=2 ttl=128 time=0.340 ms
64 bytes from 10.255.240.131: icmp_seq=3 ttl=128 time=0.323 ms
64 bytes from 10.255.240.131: icmp_seq=4 ttl=128 time=0.316 ms
64 bytes from 10.255.240.131: icmp_seq=5 ttl=128 time=0.336 ms
64 bytes from 10.255.240.131: icmp_seq=6 ttl=128 time=0.314 ms

--- 10.255.240.131 ping statistics ---
6 packets transmitted, 6 received, 0% packet loss, time 4995ms
rtt min/avg/max/mdev = 0.314/0.364/0.559/0.090 ms
[root@localhost root]# ping 10.1.1.50
PING 10.1.1.50 (10.1.1.50) 56(84) bytes of data.
64 bytes from 10.1.1.50: icmp_seq=1 ttl=62 time=4.36 ms
64 bytes from 10.1.1.50: icmp_seq=2 ttl=62 time=4.41 ms
64 bytes from 10.1.1.50: icmp_seq=3 ttl=62 time=4.38 ms

--- 10.1.1.50 ping statistics ---
3 packets transmitted, 3 received, 0% packet loss, time 2023ms
rtt min/avg/max/mdev = 4.366/4.390/4.418/0.058 ms
[root@localhost root]# ping 10.255.240.1
PING 10.255.240.1 (10.255.240.1) 56(84) bytes of data.
64 bytes from 10.255.240.1: icmp_seq=1 ttl=255 time=3.03 ms
64 bytes from 10.255.240.1: icmp_seq=2 ttl=255 time=1.72 ms
64 bytes from 10.255.240.1: icmp_seq=3 ttl=255 time=1.70 ms

--- 10.255.240.1 ping statistics ---
3 packets transmitted, 3 received, 0% packet loss, time 2020ms
rtt min/avg/max/mdev = 1.705/2.153/3.032/0.623 ms
[root@localhost root]#

Look at my result, the above ttl shows diffreent number for different IP address.I am connected to internet by proxy server in the university.What the ttl number value means?
Is there any way to increase this??Is this related to internet speed?

jzwill · 11-17-2005, 07:25 AM

TTL stands for Time To Live. It is the maximum number of "hops" the PING will allow before it gives up. Each time the ping request reaches a new router in the path to the destination, the TTL is decremented by one. If it ever gets to zero, which is rare, then there is most likely a circular route in the path from your machine to the destination machine.

nx5000 · 11-17-2005, 07:34 AM

And the ttl you see in your statistics is the one set by the machine you ping.
So 128 is a winblows machine connected on the same network segment (no router between).
Winblows uses 128 by default
Linux uses 64. Some embended machines like Camera,.. are linux based so it is the same.

62 could be a linux machine at two routers from you.